The invention relates to improvements in fluid couplings in general, and more particularly to improvements in fluid couplings of the type wherein the male and female components can be repeatedly separated from and reattached to each other. Still more particularly, the invention relates to improvements in fluid couplings of the class wherein the separable components are provided with valves which close in response to disengagement of the one component from the other component.
German Pat. No. 33 10 385 C2, granted Aug. 23, 1990 to Bartholomew, discloses a pipe coupling wherein a valve in one of the two separably connectable components closes in automatic response to separation of the components from each other. This prevents the escape of fluid from that component which contains the valve. Such couplings are satisfactory if the direction of fluid flow does not change, e.g., if the fluid always flows from the passage of the male component into the passage of the female component. It is then sufficient to provide a valve in the passage of the male component in order to prevent the fluid from escaping when the male component is disengaged from the female component. Such couplings are unsatisfactory because an appreciable quantity of an expensive, corrosive or other fluid which should not escape into the surrounding atmosphere is free to escape if the fluid flows from the passage of the female component into the passage of the male component. Another drawback of the pipe coupling which is disclosed by Bartholomew is that the valve is rather complex and its installation in the passage of the respective component of the patented coupling involves considerable expenses.
Commonly owned German patent application Ser. No. 39 33 589 A1 of Wachter et al. (published Apr. 18, 1991) discloses a hose coupling wherein neither the male component nor the female component contains a valve. Therefore, such coupling can be taken apart only when the flow of a fluid from the passage of the female component into the passage of the male component, or in the opposite direction, is prevented by means other than valves forming part of or installed in the coupling proper.
German patent application Ser. No. 32 11 937 A1 of Weber et al. (published Nov. 25, 1982) discloses a quick release pipe coupling with two valves, one in the male component and the other in the female component. The two valves are closed when the male and female components are separated from each other. A drawback of the coupling of Weber et al. is that the installation of valves in the respective components, especially in the male component, is a highly complex operation and, therefore, the provision of a valve in the male component contributes significantly to the cost of the patented coupling.